2D S-doped g-C <sub>3</sub>N <sub>4</sub> and V <sub>2</sub>CT <sub> <i>x</i> </sub> nanocomposites for ultra-sensitive electrochemical sensing uric acid
Yilin Li, Jipeng Fan, Jiahe Peng, Yujie Zheng, Weiping Gong, Jizhou Jiang
Abstract
Accurate and sensitive detection of uric acid (UA) is crucial, as abnormal UA levels are often indicative of various diseases. This work introduces a straightforward electrochemical sensor utilizing a two-dimensional (2D) nanocomposite of S-doped g-C<sub>3</sub>N<sub>4</sub> (SCN) and V<sub>2</sub>CT<sub><i>x</i></sub> MXene (SCN/V<sub>2</sub>C), which was prepared via ball milling followed by calcination. The SCN/V<sub>2</sub>C nanocomposite demonstrates superior conductivity and a reduced band gap relative to pure g-C<sub>3</sub>N<sub>4</sub>, leading to improved electrochemical performance for UA detection. Differential pulse voltammetry (DPV) measurements revealed a limit of detection (LOD) of 1 μM for UA and a linear response range spanning from 3 μM to 1 mM. Furthermore, experimental results confirmed the excellent stability of the SCN/V<sub>2</sub>C nanocomposite. Density functional theory (DFT) calculations revealed that SCN/V<sub>2</sub>C acts as a powerful electron donor, while UA functions as an efficient electron acceptor. The electron transfer between SCN/V<sub>2</sub>C and UA is significantly greater than that with other common interfering biological molecules, leading to the highest adsorption energy of UA on the SCN/V<sub>2</sub>C surface. This strong interaction accounts for the sensor’s exceptional selectivity. This newly developed sensor provides a straightforward and highly sensitive approach for the electrochemical detection of trace levels of UA in real biological samples.